The prior art in current use in this area is either the slurry feed method or a batch process commonly known as the lockhopper feed method. In the slurry feed method, a liquid-solid mixture is pumped into the pressure vessel using more or less conventional pumps. With this arrangement the liquid required to transport the solid material may not be required in the process and may reduce process efficiency or require considerable effort to be removed before processing can begin. The previous dry feeding arrangement, the lockhopper method, is to load the material into a hopper, close and pressurize the hopper with gas, and then dump the material into the pressure vessel. The hopper remains filled with high pressure gas which must be vented in readying the hopper for the next load of material. Such venting and batch feeding of material is not desirable. Large valves at the inlet and outlet of the hopper are required; such valves, operating cyclically in the environment of pulverized solids, are generally known to have poor life and reliability.
The heart of the Kinetic Extruder invention by the above-cited co-pending patent applications is a high speed rotor that contains many converging radial channels or "sprues." Pulverized material is transported into the eye of the rotor and is centrifuged outward into the sprues. A porous compacted moving plug of the particulate material forms in the sprues and creates a seal against the high-pressure gases. The sealing action is a combined effect of both the motion of the plug and its relatively low permeability. A control nozzle structure at the distal end of the sprues acts to stabilize the moving material plug and control its outward velocity to the proper value for effective sealing.
The previous applications covering the Kinetic Extruder did not include satisfactory means to vary the mass flow of material through the Kinetic Extruder over a wide range. The ability to "throttle" the Kinetic Extruder would increase its applicability since many processes where it might be used require allowance for wide feed mass flow variations.